Before the fumble, before the two touchdown catches by Ben Watson and the breathtaking finish by Tom Brady, the fate of the Patriots rested with their defense. And so as the Buffalo Bills moved the down the field at Gillette Stadium, you couldn’t help but get the feeling that you had seen it all before.

The Patriots ultimately pulled out a rather miraculous 25-24 win over the Bills at Gillette Stadium last night, but do not be fooled. The Pats today have as many questions as ever. New England played the final 49 minutes of this game without linebacker Jerod Mayo, the centerpiece of a remodeled Patriots defense that had a slew of moving parts to begin with.

And now?

"Guys were kind of moving around everywhere," linebacker Adalius Thomas said when asked about the impact that Mayo’s injury had on the New England defense. "There were a lot of people moving around on the field."

Meanwhile, at the most pivotal time of the Patriots’ first game following the departures of Richard Seymour, Tedy Bruschi, Rodney Harrison and Mike Vrabel, among others, the Bills moved in for what should have been a kill. Only Brady’s heroics and an ill-timed fumble by Leodis McKelvin spared the Patriots from an ignominious season-opening defeat, though anyone in the NFL will tell you that a win is a win is a win.

The worrisome part? During the most pivotal stretch of what was to that point a 17-13 Buffalo lead, the Bills went 62 yards in 11 plays and took more than 6 minutes off the clock in the middle of the fourth quarter. The Bills thrice converted on third down -- on one sequence, thanks to a penalty, Buffalo converted the same third down twice -- and ultimately scored a touchdown that should have sealed a 24-13 victory with 5:32 to play. Buffalo ran at Derrick Burgess and exploited the aggressiveness of pass rushers Burgess and Tully Banta-Cain, hitting running back Fred Jackson for an 18-yard gain with a screen pass (on third and 15) in addition to what then appeared to be a decisive 10-yard touchdown strike.

"No, they’re a great team," Pats safety Brandon Meriweather said when asked if the Bills exploited any particular New England weakness on that drive. "They just executed well."

And the Patriots didn’t.

The truth? The Bills aren’t a great team. In fact, they are anything but. In the final days leading up to the season opener, the Bills fired their offensive coordinator and cut their starting left tackle. Featured back Marshawn Lynch is currently serving a three-game suspension. The Buffalo offense last night was astonishingly vanilla and nonetheless effective -- Buffalo averaged 4.7 yards per rush -- and bumbling left tackle Demetrius Bell (three penalties) seemed to thwart as many Buffalo drives as anyone wearing red and white.

And then there was this: Until the final five minutes of the game, the Buffalo defense has scored as many touchdowns (one) as the Patriots offense had.

Even with a healthy Mayo -- and that currently seems in doubt -- the early part of this season was going to require some patience with regard to the Patriots defense. There has been too much turnover for the Pats to figure this out overnight. If nothing else, last night’s game validated that, with the Patriots scrambling to pull out a victory despite holding the ball for more than 37 minutes. The New England defense allowed only 276 yards, but the Bills actually gained more yardage per play.

Over the last three years, from the 2006 season that marked the departure of Deion Branch to the 2008 season defined by Brady’s knee injury, the Patriots have been plagued by a consistent problem: their defense simply couldn’t stop someone when it mattered. They lost the 2007 AFC Championship to the Indianapolis Colts when their defense broke down in the second half, then dropped Super Bowl XLII a year later when the New York Giants drove down the field. Last year, the Patriots couldn’t stop just about anyone when it mattered, ranking among the league’s worst in an array of red-zone statistics and third-down conversion numbers.

Now they are beginning a new season highlighted by the return of Brady -- he was positively brilliant in the fourth quarter -- though the potential loss of Mayo now hovers over them. The New England defense had a chance to make plays when the Pats needed them most last night, but they failed to produce when it mattered. Only the magic of Brady and the ineptitude of the Bills ultimately saved them, which might be a familiar theme of this young season as they try to replace their old defense with the new.

"That’s not exactly the way you draw 'em up," Belichick said.

But in the early part of this season, that might just be what you get.